Transmission device for a horological mechanism

ABSTRACT

A transmission device for converting vibratory movement into rotary movement in a horological mechanism, comprising at least one oscillated magnetized member and one index wheel presenting at least one toothed track, both being of magnetizable material, and both having periodically repeated teeth or poles of the same pitch thereon, wherein the said magnetized member has a comb formed into a plurality of individual poles, the pitch of the said poles being equal to the pitch of the teeth on the said track so that all the poles of the magnetized member are simultaneously in the same relative positions with respect to the teeth of the track.

United States Patent Raval 51 Nov. 4, 1975 TRANSMISSION DEVICE FOR A 3,451,280 6/1969 11mm 58/l 16 M x HORODOGICAL MECHAMSM 3,474,270 10/1969 Dietsch 58H 16 M x 3,518,464 6/1970 Kawakami et al. 310/37 X lnventorl Gaston Raval, La Neuvevillfl, 3,566,167 2/1971 Raval 310/21 Switzerland 731 Assignee: OMEGA Louis Brandt & Frere Primary EXaminerD9n9van F. Duggan S.A., Bienne, S it l Attorney, Agent, or Firmlmirie, Smiley & Linn [22] F1led. June 2, 1971 [57] ABSTRACT [21] Appl' l49l73 A transmission device for converting vibratory movement into rotary movement in a horological mecha- [30] Foreign Application Priority Data nism, comprising at least one oscillated magnetized June 24, 1970 Switzerland 9530/70 member and one index wheel Presenting least One toothed track, both being of magnetizable material, 52 us. c1. 310/21; 310/25; 310/3'7; and both having Periodically repeated teeth P0195 58/73 D; 53/23 TF of the same pitch thereon, wherein the said magne- 1511 Int. c1. nozx 7/06 tiled member has a Comb formed into a plurality of 581 Field of Search 310/21, 22, 37, 25; 58/23, individual P0189 Pitch of Said Poles being 53/23 D 23 TF, 98, 23 v, n6 equal to the pitch of the teeth on the said track so that all the poles of the magnetized member are simulta- 5 References Cited neously in the same relative positions with respect to UNITED STATES PATENTS the teeth of the track. 3,171,991 3/I965 Baumer 310/21 11 Claims, 4 Drawing Figures INVENTOR GASTON RAVAL BY TRANSMISSION DEVICE FOR A HOROLOGICAL MECHANISM The present invention concerns a device for convert ing vibratory movement into rotary movement in an horological mechanism, and comprising at least one oscillated magnetized member and an index wheel presenting at least one profiled track, also magnetized. on which there are periodically repeated teeth of uniform shape.

Several devices of this type have been proposed but it has been found that in practice such devices, made of dimensions suitable for a watch, are extremely difficult to provide. The dimensions of the teeth of the profiled track of the index wheel and of the poles of the oscillated index member are of the order of several hundredths of a millimetre. The magnetic flux and consequently the magnetic forces operating between the index member and the track on the index wheel. are very limited. For these reasons, known devices have not provided reliable starting or even an absolutely synchronous advance of the index wheel. in several known devices, two opposed poles of a permanent magnet operate on the track at opposite points of the index wheel, but even this double interaction between the driving member and the index wheel does not operate the mechanism satisfactorily.

The object of the present invention is to provide a transmission device of the above mentioned type which ensures starting in a predetermined direction, and synchronous rotation without the assistance of a particular starting mechanism.

The device of the present invention is characterised in that the said magnetized member presents a comb containing a plurality of poles, the pitch of the poles being equal to the pitch of the teeth on the wheel track so that all the poles of the magnetized member are simultaneously in the same relative positions each with respect to one of the teeth on the track. Experience has proved that such a device ensures perfect starting and indexing. If the motor effect between one or other of the poles and one or other ofthe corresponding teeth is insufficient or nil, there will certainly be a motor effect between another pole and another tooth on the track of the index wheel. it is obviously possible to adopt the same polarity for all the poles of the magnetised member and an opposite polarity for all the teeth of the track, so that there is no alternation of poles such as exists in known devices in which opposite poles of a permanent magnet operate on the soft iron track of an index wheel.

The invention will now be explained in detail with reference to the accompanying drawings in which:

FIG. 1 represents schematically the main parts of a horological mechanism,

FIG. 2 represents in detail the form of the poles ofthe (magnetized) index member and the teeth of the index wheel,

FIG. 3 is a view from above of a first embodiment of an index track, and

FIG. 4 is a view from above of another index track.

The horological movement schematically represented in FIG. 1 has a resonator in the form ofa tuning fork 1. This tuning fork is coupled to a coil 2 connected to an appropriate driving circuit 3. The members I to 3 constitute a known type of oscillator having a stable frequency in the audible range. The coil 4 of a vibratory motor is connected in series with the coil 2 and is thus traversed by an alternating or pulsating current of the frequency of the tuning fork l. The coil 4 acts on a permanent magnet S of the vibratory motor, this per manent magnet 5 being mounted on an arm 6 pivoted on an axle 7. The other end of the arm 6 carries an index member 8 mounted so as to face an index wheel track 9. The surface of the member 8 adjacent the index wheel track 9 presents a comb having poles 10. The circumferential surface ofthe index wheel presents tracks described below. forming teeth H. The relative shape and dimensions of these members are shown in FIG. 2. The or each index track 9 and the index mem ber 8 are made ofa material of high coercive force, the teeth 10 of the member 8 and the teeth ll of the index wheel track 9 being magnetized to form opposite poles such as are indicated in FlG. 2. The teeth 11 are thus attracted by the poles 10 of the member 8, which produces a coupling effect, and indexing described below between the member 8 and the index wheel track 9.

FIG. 3 represents a relatively simple embodiment of the track 9 of an index wheel. This track presents teeth 11 which each comprise a circumferential part lla and an inclined part llh. The track is formed from two series of teeth axially and circumferentially offset so that the parts llb of these teeth are axially overlapped. Each of these series of teeth is made from a stamping in which the parts of the teeth llb are cut out and bent into the form shown. The circumferential pitch between two teeth ll of the same series is equal to the pitch between two poles 10 of the index member 8. Five poles 10 are indicated in FlG. 3. It can be seen that all the poles 10 are arranged in the same position with respect to the successive teeth ll of one series on the index wheel. These poles 10 are shown in their neutral or rest positions.

When the coil 4 ofthe vibratory motor is traversed by an alternating or pulsating current, the magnet 5, the arm 6 and the index member 8, are moved in a circulatory form of vibration around the axle 7. The poles 10 thus oscillate in a direction perpendicular to the plane of the drawings FIGS. l and 2, and transversely to the circumferential direction of rotation of the index wheel in FIG. 3. The amplitude of the index member 8 is chosen so that the axial displacement of the poles I0 substantially corresponds to the axial width of the track, i.e.. the distance between the roots ofthe two series of teeth I].

When the index member 8 is oscillated, i.e., when the poles 10 are axially displaced with respect to the track of the index wheel 9, the inclined parts Nb of the teeth 1] are attracted by the poles 10, which produces a circumferential displacement of these teeth and also of the index wheel. When the amplitude of the index member 8 and poles 10 becomes large enough for the poles to clear the free ends of the parts Ilb of the teeth of the right hand series, the teeth of the left hand series are attracted by the poles l0 and remain under the poles until these latter leave the teeth of the left hand series and again attract the teeth of the right hand se ries. There is thus obtained a unidirectional motor effect which turns the index wheel in synchronism with the oscillation of the index member 8 and of its respective poles [0.

FIG. 4 represents a more complex index device which is more effective than that of FIG. 3. Teeth 11 in the form shown in FIG. 3, are disposed in another way, ie with the circumferential parts 110 back to back and the inclined parts llb directed outwardly. ln addition to the two series of teeth 1] the index wheel presents three series of teeth or of auxiliary teeth. two outer series having teeth 12 and a central series having teeth IS. The auxiliary teeth [2 are arranged half-way between the free ends of the parts 11b of two successive teeth 11. The teeth 13 are disposed between the in' clined parts of each pair of teeth 11.

This embodiment has two index members 8 the poles of which are designated by 10' and 10'' respectively. Whilst the pairs of teeth ll of the two main tracks are not offset circumferentially. the poles l and are offset by half a pitch. When the poles of one index member, for example. the teeth 10 are opposite the teeth I] of the associated main track. the poles of the other index member, in this particular case numbered 10'. are in a position which is practically midway between two successive teeth ll. The two index members are mounted on the same arm 6 of a vibratory motor and thus oscillate in synchronism and in phase in the axial direction ofthe index wheel. FIG. 4 represents the rest position of the poles of the index members.

When the index members start to oscillate with a small amplitude. the poles l0 attract the teeth of the main left hand track. When the poles l0 and 10" are slightly displaced toward the left. the poles 10' have a tendency to displace the index wheel downwardly with reference to the drawing. Likewise. the poles [0' approach the teeth 11 of the right hand track and thus exert a slight attraction downwardly. When the said poles oscillate towards the right, the poles l0 have a tendency to displace the index wheel upwardly. At the same time. the poles 10' approach the teeth 12 of the right hand auxiliary track which are now slightly displaced upwardly. The poles l0" attract the teeth l2 of the auxiliary track downwardly and thus prevent the index wheel from starting to turn the wrong way. When the amplitude of oscillation of the index member increases. the poles 10' clear the outer ends of the teeth 11. At the same time. the poles l0" sufficiently approach the teeth ll of the main right hand track to draw them downwardly. Moreover, the poles l0 approach the teeth T2 of the auxiliary left hand track and exert some attraction downwardly. The teeth ll of the main right hand track now remain under the poles l0" and are again displaced downwardly when the poles l0" oscillate towards the right and leave the ends of the teeth 11. The index wheel is thus displaced downwardly in synchronism with the oscillation of the two index members. The relatively strong poles of the auxiliary medial teeth 13 similarly prevent starting in the wrong direction. When the poles 10' are displaced inwardly i.e. to the right. they first have a tendency to displace the index wheel upwardly. This could possibly leave the teeth with their circumferential parts lla. near the poles. which could produce a start in the wrong direction. This effect. though theoretically possible. is prevented by the relatively strong poles 13 which remain under the poles of the index members after starting. so that it is impossible for the poles 10 to leave the teeth ll via their circumferential parts Ila and this induce starting in the wrong direction. Of course. all the teeth 11 and all the teeth 12 and 13 of the index wheel shown in FIG. 4 are magnetized with a polarity opposite to that of the poles l0 and 10''.

There are several modifications of the embodiment in accordance with FIG. 4 which are slightly simpler. Thus. the outer auxiliary tracks with the teeth 12 can 4 be omitted. The operation is the same, but some motor effect during normal operation and some blocking effect against a start in the wrong direction are lost. Alternatively the median auxiliary track with its teeth l3 can be omitted. the parts 1 la of the teeth 1 1 being then in direct contact.

As the index member 8 more particularly made with duplicate pole having two toothing rows, is relatively heavy. it is advantageous to use the particular type of vibratory motor such as is represented in FIG. I. However, it is possible to mount the index member 8 directly on a tine of a resonator, such as a tuning fork.

Instead of the vibratory motor shown. any other suitable vibratory motor could be used.

What i claim is:

l. A transmission device for converting vibratory movement into rotary movement in a horological mechanism. comprising at least one oscillatable magnetized member and one index wheel presenting at least one toothed track, said wheel also being of magnetizable material and both said member and said wheel having periodically repeated toothlike poles of the same pitch thereon, said magnetized member having a comb formed into a plurality of individual poles, the pitch of said poles being equal to the pitch of the teeth on the said track so that all the poles of the magnetized member are simultaneously in the same relative posi tions with respect to the teeth of the track, said track being formed from at least two stampings on which said teeth extend from the base material and are bent laterally. and means for oscillating said magnetized member in a direction substantially parallel to the axis of said index wheel.

2. A device in accordance with claim 1, wherein the track has permanently magnetised teeth of opposite polarity to the poles of the oscillated member.

3. A device in accordance with claim 1. wherein the poles of the oscillated member lie along a profile corresponding to the diameter of the index wheel.

4. A device in accordance with claim 1, comprising two symmetrical tracks and two corresponding sets of poles on the oscillated member.

5. A device in accordance with claim 4, wherein the teeth of one track are offset with respect to the teeth of the other track by half a pitch of the poles on the oscillated member.

6. A device in accordance with claim 1, wherein the said teeth each present a circumferential part and an inclined part.

7. A device in accordance with claim 5, comprising at least one auxiliary track having teeth placed between the free ends of the inclined parts of the symmetrical track teeth.

8. A device in accordance with claim 8, wherein the free end of each tooth is approximately opposite the neutral position of a pole. and wherein the circumferential parts and the said auxiliary track are opposite respective end positions of the normal oscillation of the poles.

9. A device in accordance with claim 7, comprising two auxiliary tracks each associated with a respective symmetrical track.

10. A device in accordance with claim 9 wherein the said circumferential parts of the two tracks are placed back to back at the centre of the index wheel. a third auxiliary central track being provided having one tooth between each pair of inclined parts of the adjacent teeth of the two tracks.

said or each of the said auxiliary tracks are formed from a disc stamping. 

1. A transmission device for converting vibratory movement into rotary movement in a horological mechanism, comprising at least one oscillatable magnetized member and one index wheel presenting at least one toothed track, said wheel also being of magnetizable material and both said member and said wheel having periodically repeated toothlike poles of the same pitch thereon, said magnetized member having a comb formed into a plurality of individual poles, the pitch of said poles being equal to the pitch of the teeth on the said track so that all the poles of the magnetized member are simultaneously in the same relative positions with respect to the teeth of the track, said track being formed from at least two stampings on which said teeth extend from the base material and are bent laterally, and means for oscillating said magnetized member in a direction substantially parallel to the axis of said index wheel.
 2. A device in accordance with claim 1, wherein the track has permanently magnetised teeth of opposite polarity to the poles of the oscillated member.
 3. A device in accordance with claim 1, wherein the poles of the oscillated member lie along a profile corresponding to the diameter of the index wheel.
 4. A device in accordance with claim 1, comprising two symmetrical tracks and two corresponding sets of poles on the oscillated member.
 5. A device in accordance with claim 4, wherein the teeth of one track are offset with respect to the teeth of the other track by half a pitch of the poles on the oscillated member.
 6. A device in accordance with claim 1, wherein the said teeth each present a circumferential part and an inclined part.
 7. A device in accordance with claim 5, comprising at least one auxiliary track having teeth placed between the free ends of the inclined parts of the symmetrical track teeth.
 8. A device in accordance with claim 8, wherein the free end of each tooth is approximately opposite the neutral position of a pole, and wherein the circumferential parts and the said auxiliary track are opposite respective end positions of the normal oscillation of the poles.
 9. A device in accordance with claim 7, comprising two auxiliary tracks each associated with a respective symmetrical track.
 10. A device in accordance with claim 9 wherein the said circumferential parts of the two tracks are placed back to back at the centre of the index wheel, a third auxiliary central track being provided having one tooth between each pair of inclined parts of the adjacent teeth of the two tracks.
 11. A device in accordance with claim 7, wherein the said or each of the said auxiliary tracks are formed from a disc stamping. 